This invention relates to pressure regulators for automotive fuel systems and more particularly to a simplified fuel pressure regulator.
It is known in the art relating to automotive fuel systems to provide a fuel pressure regulator for maintaining an essentially constant pressure of fuel supplied to the fuel injectors. The pressure regulator may be mounted in or on the fuel tank or at some other suitable location in the fuel system.
Pressure regulators come in many differing designs. However, one type of fuel pressure regulator has as many as fourteen or more components assembled together in a regulator assembly. In one such regulator, a rubber-like diaphragm is clamped together with a valve stop member between a lower housing and an upper cover. The diaphragm has a central valve carrier mounting a spring seat and including a pivotable valve element having a small spring biasing the valve element against a retainer. The cover has an adjusting screw which engages an upper spring guide for adjusting a spring extending between the two valve guides and biasing the valve toward a closed position. The lower housing has a valve seat engagable by the valve element when the valve is closed.
Fuel pressure admitted to a fuel chamber below the diaphragm causes the diaphragm to be lifted against the spring bias when a predetermined pressure level is reached. This opens the valve and allows excess fuel to pass through an outlet opening in the valve seat so that the predetermined pressure is maintained. The adjusting screw is used to adjust the spring force to set the predetermined control pressure for the fuel system. While the regulator performs this function well, it is desired to provide a simplified regulator design, which will accomplish the desired pressure regulating function with fewer parts and reduced assembly costs.
The present invention provides a substantially simplified pressure regulator having only three major components. One of the components is a lower housing having an open end and defining an internal fuel chamber. The housing includes a fuel return opening centrally located opposite the open end and fuel inlet openings through a lower portion of the housing.
The regulator also includes a control member comprising an imperforate resilient spring diaphragm. The control member is mounted in the open end of the housing with an outer end mounting portion brazed within the housing. The diaphragm is preferably formed of resilient sheet metal, such as is used in bellows, and includes at least one annular convolution between the mounting portion and a center portion. The center portion is configured as an inverted dome with a lower center part that acts as a valve member.
A tubular return member is adjustably mounted in the fuel return opening of the valve lower housing. An inner end of the return member forms a valve seat, preferably including a resilient seal such as an 0-ring. The 0-ring surrounds a central opening which communicates with the fuel passage through the return member.
The control member acts as a cover closing the internal fuel chamber. The control member also responds as a diaphragm to increasing pressure within the chamber to flex upwardly, by a rolling action of the convolution, which lifts the domed central portion. The regulated pressure is established or set by sliding or threading the return member upwardly, forcing the valve seat against the valve member portion of the control member diaphragm so that the spring force of the diaphragm is preloaded to a desired value. Thus, when the regulating pressure is reached, the center portion of the control member is raised off of the valve seat so excess fuel is discharged through the return member while the fuel pressure is regulated at the preset established pressure. In this simplified assembly, the control member acts as a cover, a diaphragm and a spring so that the separate spring, common in the prior art, is not required. Thus, the final assembly of the regulator is simplified by a reduction in the number of parts and reduced assembly costs.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.